最新色国产精品精品视频,中文字幕日韩一区二区不卡,亚洲有码转帖,夜夜躁日日躁狠狠久久av,中国凸偷窥xxxx自由视频

Ti-6Al-4V alloy powders were prepared by a self-developed electrode induction melting gas atomization (EIGA) equipment. Two kinds of gas atomizing nozzles, ring-hole type and ring-slit type, were used in the experiment. Different atomization pressure and power input were used. Four sets of processing parameters were designed and their effect on the powder properties was studied. The powder were sieved by 270 standard mesh (powder particle size ≤53μm) and analyst the size distribution by using MASTERSIZE 2000 Laser Particle Size Analyzer. The powder particle shape was quantified with Occhio 500NanoXY+HR Particle Size and Shape Analyzer. Results showed that optimal results were achieved with good sphericity by the combination of ring-slit nozzle with atomization pressure of 5 MPa and smelting power of 25 kW. A normal distribution of powder size was attained and the D10, D50 and D90 were 19.4μm, 31.9μm and 51.5μm, respectively. The mean Circularity and Occhio bluntness were 90.6% and 92.7%, respectively. It was found that more than 80% of powders have Occhio outgrow of 0. Further analysis of the powder by XRD, SEM, EDS and oxygen and nitrogen analyzer were carried out. The microstructure of the powder was acicular α′ martensite with random orientations. The amount of hollow powder is extremely small. The powder composition is practically same as the ingot with a low oxygen content, which satisfies the requirements of the SLM process. The Ti-6Al-4V powder achieved by optimal process was used for Selective Laser Melting and the relative density, surface roughness and microhardness are 99.02% and 4.89 μm, and 352.5 HV0.5 respectively.